Live Streaming over USB on Ubuntu and Linux, NVIDIA Jetson

Hello again,

I have an update on the situation.

The Spot CORE has an output HDMI port and I used it to connect an external monitor for testing purposes and shazam! it does work this way. Is there any reason for this ?

I checked again and it does not work when the monitor is plugged out.

I read somewhere that Xorg would not start unless a monitor was plugged in, so I tried starting it manually to see if that would solve the issue, but it doesn’t.

Maybe someone with better knowledge would know what it means ?

I juste checked the thetauvc.c file and indeed both lines you pointed out were missing. I added them and ran make clean && make to rebuild it but it doesn’t seem to have done anything.

nicodax

sorry about my earlier post. I got confused for a moment and thought you were using the THETA X instead of the THETA Z1. I deleted my earlier post.

I don’t have a good solution right now.

I don’t know about X.org monitor issues. Hopefully, someone else will be able to comment on this. You could also try an X.org-specific group on Reddit or stackoverflow. It seems like the core problem is using v4l2loopback with X.org without a monitor.

If it works with the monitor, maybe try a dummy HDMI plug as part of the debugging process and see if it works without a monitor and just the dummy plug?

Are you unable to use gstthetauvc ?

Does docker prevent you from using libusb, libuvc directly?


I do not use docker. I just searched for ideas about how to access USB devices on Docker and this post came up.


I’m reaching the limits of the knowledge that I can offer. However, feel free to keep posting as there are other people more knowledgeable than I am. It may take some time to get an answer. Just letting you know that my ideas may waste your time, so choose the best course.

Hello all!

I fixed the issue. It was actually quite simple, I just did not know this was a thing.

Apparently, there is a llinux user group called plugdev that allows access to USB devices from an SSH session. I only had to run this command:

sudo usermod -aG plugdev [SPOT_CORE_USER]

Now everything works fine.

Thanks a lot @craig for your availability, this meant a lot to me.

Take care!

2 Likes

Thank you for posting the solution.

I was not aware of the plugdev group. This will help other Spot users.

have a great holiday seasoon.

tip for gstthetauvc on Jetson Xavier NX

credit alex-uam
reference on github issue

problem

I have compiled the gstthetauvc plugin and am attempting to run it on a Jetson Xavier NX, however I receive the error :

ERROR: from element /GstPipeline:pipeline0/GstThetauvcsrc:thetauvcsrc0: Found 1 Theta(s), but none available.

I have successfully gotten it running on a Jetson Xavier AGX, as well as an Ubuntu desktop PC. Just wondering if there are any obvious steps that I’ve missed for the NX? Possibly permission issues?

solution

We managed to find the solution. Turns out it was as simple as setting an environmental variable in bash:

export LD_LIBRARY_PATH=/usr/local/lib

For whatever reason, this is automatically set on Intel based Ubuntu, and the Xavier AGX series board, but not the NX!

:+1::fire:


other

on my (craig) system, this is my /etc/ld.so.conf.d/libc.conf

 cd /etc/ld.so.conf.d/
craig@jetpack-4:/etc/ld.so.conf.d$ ls
aarch64-linux-gnu.conf             fakeroot-aarch64-linux-gnu.conf
aarch64-linux-gnu_EGL.conf         libc.conf
aarch64-linux-gnu_GL.conf          nvidia-tegra.conf
cuda-10-2.conf                     vpi1.conf
fakechroot-aarch64-linux-gnu.conf
craig@jetpack-4:/etc/ld.so.conf.d$ cat libc.conf 
# libc default configuration
/usr/local/lib